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PostPosted: Mon Apr 09, 2018 8:09 pm 
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Hi all:

Currently working on Trumpeter 1:350 Hancock CV-19. Bought the beautiful Model Monkey's island superstructure in Frosted Ultra Detail (FUD) from Shapeways. Read Model Monkey's advice on clean-up and paints etc. Using Vallejo acrylics on rest of model but found I liked the application of Tamiya Grey Surface Primer #87026 underneath. Read Steve's (Model Monkey) FAQ advice suggesting Tamiya primer might cause a problem - I also have conflicting advice from a Civil War model railroading source for painting 3-d FUD locomotive parts from Shapeways - that source says soak in Bestine (Steve says no to Bestine) and use Tamiya surface primer. I compromised and followed Steve's advice in that I set the superstructure in direct sun for 5 hours, then cleaned with Dawn, but then I departed from Steve's recommendation and sprayed on Tamiya from the can (instead of Vallejo's Liquid Surface Primer). Guess what? Steve was right!! See attached photos to show the pebbled surfaces that resulted. Not sure if this is reaction with the primer or particles and roughness I missed seeing on the part after cleaning. I was concerned but not panicking yet. I also have read the comments by Steve and others suggesting use of an air eraser with baking soda as the abrasive to clean off and smooth the surfaces, so I trotted over to Harbor Freight and bought one for $24.99.

My questions are these:
- Can the air eraser fix this problem? It seems to be preferable to using tiny sanding sticks and pads to remove the particles and pebbled patterns.
- Is there anything to be careful of when using the air eraser on the FUD material - e.g. can I wear holes in the surface if not careful? What pressure is best?
- I have a pretty large metal spray booth (dual exhaust), but should one use the air eraser in a spray booth? I am guessing the bicarb will clog the filters faster than paint, if nothing else.
- If the air eraser works, should I pile on more Tamiya Surface Primer or switch to the Vallejo Acrylic primer from an airbrush.

Gotta say I love the detail on this part that really pops when color is applied, even with the pebbles!

Thanks in advance for any help or advice - and my advice to those contemplating 3 D parts - go for it but follow Steve's advice the whole way

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PostPosted: Mon Apr 09, 2018 9:02 pm 
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Hi All Again:

Just realized I didn't actually get my photos posted with the main topic post - just figured out you have to hit submit button for photos to include them with a post! Here they are:

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PostPosted: Mon Apr 09, 2018 9:04 pm 
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Still can't tell if I am posting photo attachments or not. Looks like I need some help from the moderators.

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PostPosted: Mon Apr 09, 2018 10:53 pm 
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Attachment:
File comment: Overview shot of the part...
Hancock CV19 - Island Structure.jpg
Hancock CV19 - Island Structure.jpg [ 73.82 KiB | Viewed 601 times ]


okay. I got it now - size matters! Was missing the message that pic files must be less than 400 kb and less than 1200 x 1200 pixels. Today's phone cams have too many pixels! Here are photos resized.

Attachment:
File comment: Close-up of rough areas...
Hancock CV19 Super-p1.jpg
Hancock CV19 Super-p1.jpg [ 182.44 KiB | Viewed 601 times ]


Attachment:
File comment: Stack and mast area with pebble problem....
Hancock CV19 Super- p4.jpg
Hancock CV19 Super- p4.jpg [ 187.67 KiB | Viewed 601 times ]

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PostPosted: Tue Apr 10, 2018 6:51 am 
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That does not look like a primer reaction to me, it appears to be surface artifacts from printing. I'm not sure how that material sands, but I'd say that's what needs to be done, or the air eraser as you mentioned.

A note on the Vallejo primer: it sprays great and looks great when dry, but you can't sand it. It doesn't feather, just rolls up and peels. I recommend the Badger Stynylrez primer. It goes on much like the Vallejo, but once it's dry it sands and feathers wonderfully. It's the only primer we use at work on our 3D prints and laser cut acrylic.

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PostPosted: Tue Apr 10, 2018 8:10 am 
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I have run into the same problem and agree with Devin - it is a problem with the printing and not the primer. The translucent nature of the Frosted Ultra Detail material conceals the defects until the primer is applied, but the roughness can seen and felt beforehand with a careful examination. I have purchased several hundred dollars worth of Shapeways parts for a 1/72 scale project, and in my experience the roughness is always there to varying degrees. The severity runs from minor annoyance to rendering the part completely unusable. In 1/72 this can be dealt with by repeated sanding and priming, deconstructing the part and replacing detail as needed. I don't see how fine detail or fragile assemblies can survive for smaller scales.

Some pictures to illustrate the problems, if I can get the pictures to appear (much frustration with this so apologies in advance). These are Type 89 12.7 cm guns which are about 3.5 " (8.5 cm) in length. The first gun was made with White Strong & Flexible. All the WSF parts I purchased exhibited this problem. As you can see, this material is not suitable for modeling. The part was not used. Money wasted, lesson learned - stay away from WSF! The second picture is another gun from a different designer in Frosted Ultra Detail. Printing artifact is present on several surfaces. Flaws seem to be worse on underhanging surfaces. The third picture shows the same gun after much filing and sanding. The gun was cut apart and all the surfaces sanded smooth. Once primer showed the imperfections were removed all the lost surface detail was replaced with Evergreen and wire.


Attachments:
File comment: WSF gun.
Gun1.jpg
Gun1.jpg [ 170.14 KiB | Viewed 527 times ]
File comment: FUD gun.
Gun2.jpg
Gun2.jpg [ 194.22 KiB | Viewed 527 times ]
File comment: The FUD gun after correcting, in place.
Gun3.jpg
Gun3.jpg [ 218.17 KiB | Viewed 527 times ]
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PostPosted: Tue Apr 10, 2018 9:49 am 
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That's a major problem and frustration with most 3-D printed items - especially those from Shapeways. You'll probably get that textured surface (treadplate) where it shows and is difficult to get rid of. I have gotten figures from Shapeways with this kind of texture across the body and face, making the figure pretty well useless, unless you replace the head with a cast resin one. Sometimes the texture runs through an area where there is surface detail and again, is difficult to impossible to erase. I've bought many items from Shapeways, by different designers, and they've all had texture, in varying amounts, in hard to get at areas. Shapeways always show a CAD rendering of the item in their catalogue which looks great, instead of a pic of a primed example of the item which would show any blemishes. I find 3DModelparts much better in that respect, in that they show pics of the real thing, and their items don't have as much artifacts.
:wave_1:


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PostPosted: Tue Apr 10, 2018 10:48 am 
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Model Monkey
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Hi Mark,

Thanks for your patronage!

I tend to agree with Devin and Inchhigh, the surface looks more like the kind of surface roughness caused by contact with the waxy supporting material during printing rather than a chemical reaction. While harsh chemicals like acetone and Bestine (heptane) are known to create an "orangepeel" surface in products printed in Frosted Detail plastics (FUD and FXD), I think your Tamiya primer is probably not the big cause here. Either way, I think smoothing with an air eraser rather than sanding is a very good option. Careful use of an air eraser can remove the roughness while helping to preserve any detail, especially in hard-to-reach places.

Underlying surfaces that come into contact with the waxy supporting material during printing will be rougher. During printing, the acrylic plastic and waxy support material are extruded nearly simultaneously by the 3D printer. The wax is still hot and a bit soft when the acrylic is laid on it and the wax deforms very slightly and irregularly causing the acrylic to have the rougher surface at the point of contact. The wax is melted away in a low temperature oven at the factory before the product is shipped to the customer leaving just the acrylic plastic.

You can see in this rendering how the waxy material, in yellow, supports the acrylic product in red during printing. Any surface area shown in orange is likely to have a rougher surface.

Attachment:
V4WjOAC.jpg
V4WjOAC.jpg [ 52.12 KiB | Viewed 489 times ]

Notice how surfaces in the island that do not have features above them are very smooth, such as the flag lockers, splinter shielding and funnel cap. Those are tell-tale signs that the surface roughness elsewhere is due to hot wax contact during printing rather than a chemical interaction with the Tamiya primer.

Regarding "Strong and Flexible" plastic (S&F or WSF), please be advised that WSF is a kind of nylon printed in a very different way than FUD or FXD. There is no waxy supporting material involved in WSF printing. However, the layers are much thicker and the resolution less fine. This creates a noticeable "stair-step" appearance on any surface that is not vertical. The technology used is commonly found in low-end 3D printers used by some hobbyists and schools. Because of WSF's characteristics, I do not recommend it for static display models for a number of reasons, most importantly, the reason described by Inchhigh, the surface can be so rough as to render the part unsatisfactory for that purpose.

However, many designers offer products printed in WSF because it does meet certain needs of some modelers. Only a few of my designs are available in that material, mostly for very large products intended for use on radio control models that will take a beating, for customers who require strength and durability over surface smoothness and fine detail.

WSF, being nylon, does not smooth easily, if at all. A method that has worked for some modelers is to apply thin coats of primer meant specifically for nylon, then smoothing the primer rather than the plastic. This process is not useful for smoothing surfaces of many objects depending on their features and geometry.

For static display models, where detail is more important than strength, I recommend Frosted Detail acrylic plastic (FUD and FXD).

FUD and FXD products are made in higher-end 3D printers costing $70,000-90,000 USD which is typically why only large companies like Shapeways have access to them. The typical 3D designer cannot afford such a machine. There are other, less costly machines that use different technology that does not require waxy supporting material. But their printing platter is relative small and they often cannot print objects like superstructures or larger turrets even in 1/350 scale.

Having said all this, I still advise against using Bestine (heptane), Goo Gone or acetone to prepare products printed in FUD or FXD. Those products are known to craze and even melt Frosted Detail acrylic plastic.

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-Steve Larsen

Complete catalog of over 1600 designs for modelers:
https://modelmonkey.wixsite.com/modelmonkey


Last edited by ModelMonkey on Tue Apr 10, 2018 12:12 pm, edited 2 times in total.

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PostPosted: Tue Apr 10, 2018 12:00 pm 
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Thanks to Inchhigh, Devin and Steve for your detailed and thoughtful replies. I have found this forum to be a welcoming venue for new scale modelers such as myself, and I consider it a wonderful resource. It looks like I am going to cautiously proceed with the air eraser and then decide what to do about re-priming. If the defects are due to surface residue and not chemical reaction with the Tamiya primer, it would seem I could re-coat with Tamiya after the cleaning and smoothing.

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PostPosted: Tue Apr 10, 2018 12:02 pm 
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Thanks also to Drasticplastic for your reply.

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PostPosted: Tue Apr 10, 2018 12:21 pm 
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Model Monkey
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jmrcss1 wrote:
Thanks to Inchhigh, Devin and Steve for your detailed and thoughtful replies. I have found this forum to be a welcoming venue for new scale modelers such as myself, and I consider it a wonderful resource. It looks like I am going to cautiously proceed with the air eraser and then decide what to do about re-priming. If the defects are due to surface residue and not chemical reaction with the Tamiya primer, it would seem I could re-coat with Tamiya after the cleaning and smoothing.

Yes, I think you are "good to go" with Tamiya primer after using your air eraser.

Thank you for your thoughtful descriptions and excellent photos. This discussion definitely helps alert modelers to some of the characteristics and issues of FUD and FXD, and why I don't recommend WSF for static display models. You also give me an opportunity to describe why the surface looks that way and suggest a solution. As the technology continues to mature, we will one day certainly achieve a state where surface smoothness issues will be a thing of the past. Until then, the air eraser can be our new best friend.

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Complete catalog of over 1600 designs for modelers:
https://modelmonkey.wixsite.com/modelmonkey


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PostPosted: Tue Apr 17, 2018 2:13 am 
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I've had to deal with this problem on a regular basis, so I know the frustration that you're feeling. An air erasure with baking soda works well with taking off the waxy surface of the parts, but you have to keep a few things in mind. Baking soda can easily clog the air eraser. Make sure there are no clumps, or sift it through a fine screen first. Use the air eraser in a confined space with good ventilation because the baking soda goes everywhere! Use swimming goggles or a snorkeling mask to seal off your eyes from baking soda dust. It stings almost as badly as salt if it gets in your eyes.

Other than that, all 3D parts that I've seen have had some sort of layering effect that leaves steps on curves. This is where you'll mostly get into scraping with a knife blade, or sanding. Use light coats of primer until you get a reasonably smooth surface, then use a heavier coat with a light sanding after that dries with 200 or finer wet-or-dry paper, used wet. I mostly use Mr. Surfacer 500 or 1000 primer.

With all due respect to Model Monkey and most other 3D designers, one-piece assemblies are impressive as all get out, but I'd be more impressed with these parts if they were designed with more thought in mind regarding the problems with cleaning up the surface gunk left by the printing process. For example, I doubt that water tight door on the side of the island is going to look anything like how it was drawn by the time you're finished. Some things are better done in etch.

Good Luck.

Mike


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PostPosted: Tue Apr 17, 2018 7:00 am 
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Yeah, I agree...I see some designs that look like they replicate the real thing down to the last nut and bolt. They look REALLY impressive in the render but print like poop. The second part of this is how the item is oriented to print. Early on, I designed to minimize space and thus reduce cost. I didn't think too much about the orientation... So I had two turrets up and one upside down... that resulted in surface roughness on the topside of the upside-down turret. Once I had a few examples under my belt I changed my design philosophy of orienting the most visible surface up, putting items close together, and also dumbing down the complexity of the part into multiple pieces that are assembled. For example, were I to model a boat hull, I would orient it upside-down and then have the deck piece right side up separate from the hull.


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PostPosted: Tue Apr 17, 2018 7:23 am 
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Mike makes some good points. I'd like to try to address them. And thanks for your patronage, Mike!

Deciding on the configuration of parts is based on a number of factors, ease of cleaning being just one important consideration among many. When a product is being created, the designer has to balance competing considerations and, regrettably with superstructures, ease of cleaning and painting is often overtaken by some of the other considerations. I recognize that this can create conditions that make the product difficult to access for cleaning and surface smoothing. When creating a design, I do carefully consider this problem. Sometimes, other considerations win out.

1. Printing requirements. First and foremost, the designer has to meet printing requirements for the intended material. If Shapeways can't print it, the modeler can't have it. Meeting printing requirements is usually the most important design consideration. Meeting printing requirements requires most superstructure parts I design to be offered fully assembled. Although there are several, printing requirements typically come down to two product-killing issues:

a. The product has to fit in the printer. A large, more complex product like a superstructure, if separated into decks with each part laid out side by side, creates a "parts array" that many times is too big for the printer for the intended material. In 1/350, the parts usually have to fit in the printer space meeting the requirements for Frosted Ultra Detail (FUD). For 1/700, to achieve any meaningful detail, it has to fit for Frosted Extreme Detail (FXD), which is a much smaller platter space than for FUD. Superstructures separated into decks are too often too big to print.

b. Features are fully supported to survive cleaning at the factory. Because of the geometry of some features (thinness or length), those features have to be supported on more than one side. Sometimes they have to be supported on at least three sides. When it comes to thin bulkheads for 1/700 scale superstructures, for example, this sometimes requires that bulkheads be sandwiched between decks, tripod masts to be attached to some other firm feature at both top and bottom, and splinter shielding be attached to a deck or platform. This is why the Essex SCB islands have bridge and PriFly decks (open windows) that are integrated with the island. They would be destroyed in cleaning if they weren't supported all around.

2. Cost. Shapeways charges a handling fee for each part printed in a set. This is because Shapeways cleans each part by hand. More parts adds to the effort in turn adding to the cost. As you know, 3D-printing remains expensive, too expensive for many modelers. The fee for multiple parts can quickly escalate the cost of an already expensive product to the point where it is effectively unaffordable to most modelers. Compared to assembled superstructures, very expensive, multi-part products (e.g. New Jersey round bridge, USS Portland and Baltimore class cruiser superstructures) have not sold well. Cost remains the biggest factor killing sales.

3. Customer demand. There's no easy way to say it, the market is aging. Sales data and customer communication indicates that most customers are over 45 years old, many retired. And with an aging customer base, I consider ways to help customers with age-related concerns. As the market ages, there are increasing demands for products that require little or no assembly, are fully detailed, and don't require the modeler to install "fiddly bits", specifically do not require using photo-etch doors, especially in 1/700 scale. Several customers reported they were very excited by how the inclusion of open doors and open scuttles adds to the realistic appearance of some of my earlier designs (e.g. Lexington and Saratoga islands). But several customers reported in no uncertain words that they needed models that didn't require the addition of photo-etch doors, especially in 1/700 scale. Many modelers asked explicitly for the inclusion of integrated open doors, even though those doors can be easily damaged during cleaning and smoothing. Including details such as integrated doors helps meet the needs of an aging market. This consideration seems to becoming more important with time.

I will continue to consider accessibility for painting and surface smoothing with each design as I create it. That consideration may not carry the day in making the product a reality.

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-Steve Larsen

Complete catalog of over 1600 designs for modelers:
https://modelmonkey.wixsite.com/modelmonkey


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PostPosted: Tue Apr 17, 2018 5:56 pm 
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Steve,

I hope you didn't take my comments as being too harsh, or overly critical, and I didn't intend for anyone to think that all of my problems were with your products. They weren't. My comments were only intended to highlight the limitations of the medium. There is also the complication of the different resolutions of different processes. The 3D accessory sets that I've gotten from Free Time Hobbies have had none of the waxy issues and have had very fine layer transitions, for example. I appreciate that you have to deal with making them widely available at a reasonable price.

Mike


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PostPosted: Wed Apr 18, 2018 6:29 am 
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Model Monkey
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We're good, Mike!

I appreciate the opportunity to contribute to the discussion. Thanks for your contribution, too. The medium certainly has limitations. I think awareness helps overcome those limitations.

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-Steve Larsen

Complete catalog of over 1600 designs for modelers:
https://modelmonkey.wixsite.com/modelmonkey


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